Street Trees

Most of the photos of great streets seen on these pages feature street trees. Trees are among the most important – and overlooked – features of urban streets. Visual preference surveys routinely reveal that citizens greatly prefer streets that feature mature canopy trees and other vegetation to streets that do not.

Traffic calming. Properly-placed street trees frame and define the street as perceived by drivers. The vertical edge to the view plane that the trees provide reduces the apparent width of the street, increasing “friction” and lowering average speeds.

In some cases, the added property tax proceeds from increased valuations may recoup much of the cost of installing and maintaining the trees.

Pavement preservation. The shading of pavements by street trees increases pavement life, reducing long term costs of street maintenance.

Reduced storm water run off. Street trees can significantly reduce the percentage of rain water that reaches the ground below them. The actual percentage is greater for light rains and is highest during the early stages of extended rain events.

Credit: Walkable Communities

While this may not reduce the size of required street drainage systems, it does reduce the total amount of storm water delivered into street drainage systems over the course of a typical growing season.

Improved air quality. Trees absorb carbon monoxide and other air borne pollutants.

Intangible public benefits. Although difficult to measure, the public reaps significant benefits from the improved attractiveness and shading of public streets that street trees provide.

Tree Guidelines for San Joaquin Valley Communities, by E. Gregory McPherson, James R. Simpson, Paula J. Peper, QingfuXiao, Western Center for Urban Forest Research and Education, Published by the Local Government Commission.